Combined high‐intensity interval training as an obesity‐management strategy for adolescents

ABSTRACT Effective and safe exercise protocols for obesity management in adolescents are imperative. This study aimed to analyse compliance, efficacy, and safety of combined high‐intensity interval training circuit (HIIT) in the management of obesity (including overweight) in adolescents, compared to traditional training (TT). Data from 55 adolescents (47.3% girls) (TT n = 31; HIIT n = 24), aged 12–18 (mean age of 14.3 ± 1.7), with overweight and obesity (median BMI z‐score of 2.95), were assessed at baseline and month 6 (Clinicaltrials.gov/NCT02941770). During the 6‐month intervention, participants in both exercise groups attended two exercise sessions/week (60 min/session) along with a set of appointments with a paediatrician, nutritionist, and exercise physiologist. Forty‐six participants completed the intervention (TT n = 23; HIIT n = 23). Exercise session attendance (≥80%) was significantly higher among HIIT participants (73.9 vs. 13.0%, p < .001). HIIT, but not TT, showed a significant decrease in BMI z‐score ( d = 0.40, p < .001), body fat mass (BFM, %) ( d = 0.41, p = .001), and trunk fat mass ( d = 0.56, p < .001), as well as a significant increase in muscle mass (MM, %) ( d = 0.28, p = .001) between baseline and 6 months. According to generalized estimating equations, time‐by‐attendance interactions (instead of time‐by group) were found in BMI z‐score ( β = 0.25, 95%CI: 0.17, 0.33), BFM ( β = 2.29, 95%CI: 1.02, 3.56), trunk fat mass ( β = 2.94, 95%CI: 1.70, 4.18), and MM ( β = −1.16, 95%CI: −1.87, −0.45). No adverse events were reported during HIIT sessions. Although compliance may mediate the impact of an exercise protocol on health‐related outcomes, HIIT showed to be safe, with higher compliance compared to TT, which may result in improved outcomes overtime.